Surveillance and alarm system

ABSTRACT

A surveillance and alarm system having a plurality of entry responsive means for detecting entry into predetermined locations throughout a building, and indicating means for maintaining surveillance on the building and for indicating the number and locations of entries into the locations. Means are also provided for maintaining a closed series loop circuit between entry responsive means and for indicating any interruption in signal in the series loop circuit. The system further includes an external signalling device responsive to an entry or an interruption in signal, and means for selecting any one of several system mode variations.

O United States Patent [151 3,648,268 Paull Mar. 7, 1972 [54] SURVEILLANCE AND ALARM SYSTEM 3,234,535 2/1966 Schordine ..340/2l3 72 inventor: Melvin Paull, 8001 Rosiline Drive, St. ggigig $1338 m 'g ils '5 63105 3,540,043 11/1970 Crosthwait 340/213 x [22] Filed: Nov. 3, 1969 r Primary ExaminerDavid L. Trafton [21] Appl #73368 Attorney-Kingsland, Rogers, Ezell, Eilers and Robbins 1521 U.S.Cl. ..340/276, 340/214, 340/409, ABSTRACT [51] Int. Cl A surveillance and alarm system having a plurality of entry [58] Field ofseamh 3/213 l 214 409 412 responsive means for detecting entry into predetermined loca- 340/353 1 4 27 2 tions throughout a building, and indicating means for maintaining surveillance on the building and for indicating the number and locations of entries into the locations. Means are [56] References C'ted also provided for maintaining a closed series loop circuit UNITED STATES PATENTS between entry responsive means and for indicating any interruption in signal in the series loop circuit. The system further Gilligan includes an external signalling device responsive to an entry of 3 9 8/1942 an interruption in signal, and means for selecting any one of 2,351,587 6/1944 several system mode variations. 2,492,432 12/1949 2,894,251 7/1959 Ruffle ..340/2l4 X 43 Claims, 1 Drawing Figure Patented March 7, 1972 3,648,268

2 Sheets-Sheet 1 PART I INVEA/TOP.

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SURVEILLANCE AND ALARM SYSTEM SUMMARY OF THE INVENTION The surveillance and alarm system of this invention comprises a plurality of station switches at predetermined locations throughout the building in which the system is installed and responsive to entries through the locations, such as doors or windows, where the station switches at located. A relay having a plurality of sets of contacts is associated with each station switch. Each station switch is connected to its associated relay and to the other station switch and relay combinations in a closed series loop circuit, which circuit is energized when the system is set to any of its mode variations. Also included in the closed series loop circuit is the coil of a line out relay which is energized by the signal in the closed series loop circuit, placing the line out relay in its normally closed position. The line out relay is actuated by an interruption in the signal in the closed series loopcircuit such as for example, when a line in the loop is cut.

Manual switches are provided for setting the system in any one of several possible mode variations, such as the surveillance mode or burglar alarm mode. One of the manual switches, the key switch, is mounted on one of the outside doors of the building and is used to set the system in the burglar alarm mode. Most of the other manual switches are located in a convenient place such as on a control panel.

Various signalling devices and indicators are included in the system and operate depending on the mode setting. An external signalling device which could be a siren, a bell, a connection to the police station or another similar type of signalling device, is set to operate when the system is in the burglar alarm mode. The system is also provided with a panic switch, which when closed will energize the external signalling device; and an inside alarm set switch, which when closed will energize the external signalling device whenever any one or more of the station switch and relay combinations or the line out relay is actuated, regardless of the system mode setting.

Indicators responsive to the actuation of each station switch and relay combination, and the line out relay, indicate the number and location of entries. 1

Other features of the invention are a test mode to test the operation of the relay associated with each station switch, and a signal release to reset the system.

Thus, it will become clear that this invention is both an alarm system and a surveillance system which may be combined in various mode settings, and includes features designed to minimize failure of the system.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a schematic diagram of the surveillance and alarm system of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawing there is shown a power supply 10, a control panel 11, an external signalling device 12, and a plurality of station switches 21-30. The station switches 21-30 are located at various positions throughout the building such as at the doors or windows or wherever protection is desired. While in this embodiment of the invention there is described a system having stations, obviously any number of stations may be used. Only the stations 21, 22 and are shown on the diagram. The remaining stations 23-29, are identical to the stations 21, 22 and 30 and were therefore omitted.

POWER SUPPLY The power supply 10 includes a transformer 31 which drops the line voltage to a rectifier network 32. The signal from the rectifier network 32 is applied to the coil 33 of a relay 34. A resistor is in series with the coil 33 of the relay 34 to reduce the voltage across the coil 33 to an amount less than the voltage across the coils of the other relays in the system. This will cause the relay 34 to deenergize and switch to the auxiliary power supply before the other relays in the system deenergize. The rectified voltage is fed from the bottom of the resistor 35 through a line 36 to the normally closed terminal of the contacts 37 of the relay 34. The drawing depicts the relay 34 in the normally closed position. A battery 38 is connected by a line 39 to the normally open terminal of the relay 34 and acts as a secondary or backup power supply should the line power for any reason be interrupted. A lead 40 which is the power lead to the surveillance and alarm system is connected to the center terminal of the relay'34. Thus, it can be seen from the drawing that the rectified voltage at the coil 33 of the relay 34 holds the contacts 37 in the normally closed position. With the contacts 37 in the normally closed position, the rectified voltage is fed from the bottom of the resistor 35 through the line 36 and the normally closed and center terminals of the contacts 37 of the relay 34 to the line 40. If for any reason the line power is interruped, the coil 33 of the relay 34 will deenergize placing the relay 34 in the normally open position. With the relay 34 in the normally open position, the voltage from the battery 38 is fed through the line 39 and the normally open and center terminals of the contacts 37 of the relay 34 to the line 40.

The remainder of the surveillance and alarm system will be described with the various manual switches positioned as they would be under normal operating conditions. Unless it is specified to the contrary, it may be assumed that each of the relays shown in the drawings is shown in its normally closed position.

BURGLAR ALARM MODE There are seven manual switches shown in the drawing. These switches are: the key switch 50, the on-off switch 51, the panic switch 52, the inside alarm set switch 53, the reset switch 54, the audio release switch 55, and the test switch 56. By appropriately setting these switches, various modes of operation may be selected. The first mode which will be described is the burglar alarm mode. For this mode, the key switch 50 is placed in the burglar alarm position, (this is where the wiper arm 60 of the key switch 50 joins the center terminal 61 to the alarm terminal 62) the surveillance switch 51 in the closed position, and all of the other manual switches 52, 53, 54, 55, and 56 in the open position.

With the key switch 50 in the burglar alarm position and the on 7 off switch 51 in the on position, the signal on line 40 is fed through a line 63, a line 64, the on off switch 51, a line 65, and a line 66 to reset relay 67. The reset relay 67 has a coil 68 and four sets of contacts A, B, C, and D, with the reset relay 67 deenergized in its normally closed position, no signal having as yet been applied to the coil 68, the signal on the line 66 is fed through the center and normally closed terminals of the set of contacts C of the reset relay 67 through a line 69 to a line 70. As will be seen, it is the line 70 which supplied holding voltage to each of the relays associated with the station switches21 through 30 and supplies the voltage to actuate the externalsignalling device 12 when the normally open contact of any one of the station switches 21-30 is closed.

When the on-off switch 51 is closed, an initial pulse appears on the line 66 which is fed through a capacitor 71 and lines 72 and 73 to the coil of a line out relay which will be hereinafter described.

Each of the station switches 21-30 has three contacts: a center contact, a normally open contact, and a normally closed contact. Associated with each of the station switches 21-30, is a relay 75 having a coil 76 and four sets of contacts A, B, C, and D. The coil 76 has in parallel with it a capacitor 77. The line 70 is connected to the center terminal of the set of contacts A of each of the relays 75 with appropriate leads 80, 81, etc.

The signal on the line 66 is fed through a line to the center terminal of the station switch 21 and the normally open terminal of the set of contacts D of each of the relays 75 associated with the station switches 21-30. Using the station switch 21 and its associated relay 75 as an example, the signal on the line 85 is fed through a line 86 to a line 87. One end of the line 87 is connected to the center terminal of the station switch 21 and the other end is connected to the normally open terminal of the set of contacts D of the relay 75. With the station switch 21 in the normally closed position, the signal on the line 87 is fed through the center and normally closed terminals of the station switch 21, a line 88, the normally closed and center terminals of the set of contacts D of the relay 75, and a line 89 to the center terminal of the station switch 22. With the station switch 22 likewise in the normally closed position, the signal on the line 89 is fed through the center and normally closed terminals of station switch 22, a line 90, the normally closed and center terminal of the set of contacts D of the relay 75 associated with the station switch 22, and a line 91 to the center terminal of the station switch 23. In like manner, the signal is carried through each of the station switches and set of contacts D of the relay 75 associated therewith forming a closed series loop circuit the purpose of which will be explained.

With the station switch 30 in the normally closed position, the signal at its center and normally closed terminals is fed through a line 92, the normally closed and center terminals of the set of contacts D of the associated relay 75, and a line 93 to the terminal 61 of the key switch 50.

With the key switch 50 in the burglar alarm position the signal on the line 93 is fed to the terminal 61 and through the wiper arm 60 to the terminal 62 of the key switch 50, and then through a line 100 to a latching relay 101. The latching relay 101 is of the type that once it is activated to one of its two possible positions, it will stay in that position until it is activated to the other position.

The latching relay 101 has two coils 102 and 103. The coil 102 is the surveillance coil and the coil 103 is the alarm coil. Each of the coils 102 and 103 has a capacitor 104 in parallel with it. The latching relay 101 is further comprised of five sets of contacts A, B, C, D, and E, each set having three terminals. The left tenninals of each of the sets will be referred to as the surveillance terminals, the right terminals will be referred to as the alarm terminals, and the middle terminals will be referred to as the center terminals.

At this point it should be noted that the key switch 50 is designed so that it requires a key to operate it, and can only be operated from outside the door. Also, to enter through the door where the key switch 50 is located requires that the key switch 50 be placed in the surveillance position. It will be seen that the position of the latching relay 101 is determined by and corresponds to the position of the key switch 50, hence prior to setting the key switch 50 in the alarm position, the latching relay 101 was in the surveillance position.

Therefore, with the latching relay 101 still in its surveillance position, the signal on the line 100 is fed through the surveillance and center terminals of the contacts C of the latching relay 101, a line 105, a diode 106, and a line 107 to the coil 68 of the reset relay 67. The coil 68 is energized placing the relay 67 in the nonnally open position. The signal at the line 105 is fed through a line 108 to the normally open terminal of the set of contacts B of the reset relay 67. With the relay 67 in the normally open position, the signal on the line 108 is fed through the normally open and center terminals of the set of contacts B of the reset relay 67, and a line 109 to the alarm coil 103 of the latching relay 101, energizing the alarm coil 103 and placing the latching relay 101 in the alarm position.

The signal on the line 40 is fed through a line 115, and now with the latching relay 67 in the alarm position, through the alarm and center terminals of the set of contacts D of the latching relay 101 and a line 116 to the line 66. When the alarm coil 103 of the latching relay 101 became energized placing the latching relay 101 in the alarm position, the electrical contact between the center and surveillance terminals of the set of contacts C of the latching relay 101 was broken, removing the signal on the coil 68 of the reset relay 67 causing the reset relay 67 to deenergize. Hence, after the latching relay 101 is placed in the alarm position the reset relay 67 returns to its normally closed position. With the reset relay 67 returned to its normally closed position the signal on the line 66 is again fed through the center and normally closed terminals of the set of contacts C of the reset relay 67, and the line 69, to the line 70, thereby maintaining the signal on the closed series loop circuit described above and which will be further described below.

At this point it should be noted that the line 66 which feeds the closed series loop circuit and the holding line 70 first received its signal through the on off switch 51, but later after the latching relay 101 is placed in its alarm position, receives the signal through the latching relay 101 independent of the on-off switch 51. Hence, it can be seen that once the latching relay 101 is placed in the alarm position, the on off switch could be opened with no loss of signal to the system.

Returning to the signal on the alarm terminal 62 of the key switch 50 and on the line connected at one end to the alarm terminal 62, the signal on the line 100 is also fed through a line 117, a diode 118, a line 119, and a line 120 to the center terminal of a set of contacts B of an audio silence relay 121.

The audio silence relay 121 has a coil 122 and two sets of contacts A and B. With the audio silence relay 121 in the normally closed position as shown, the signal on the line 120 is fed through the center and normally closed terminals of the set of contacts B of the audio silence relay 121, a line 123 and a line 124 to the center terminal of the set of contacts D of the reset relay 67. With the reset relay deenergized to the normally closed position, as explained above, the signal on the line 124 is fed through the center and nonnally closed terminals of the set of contacts D of the reset relay 67, a line 125 and a line 126, a case interlock switch 127 shown on the drawing in the normally closed position, and a line 128 to the center terminal ofa set of contacts A ofa line out relay 130.

The line out relay 130 has a coil 131 and three sets of contacts A, B, and C. As was stated above, an initial pulse was supplied to the coil 131 through the capacitor 71 which energized the coil 131 placing the line out relay 130 in its normally closed position. With the relay 130 in its normally closed position, the signal on the line 128 is fed through the center and normally closed terminal of the set of contacts A of the line out relay 130 and lines 132 and 73 to the coil 131, holding the line out relay 130 in the normally closed position. Once the line out relay 130 is closed, it will stay closed as long as there is voltage on the line 128. If for any reason the voltage on the line 128 is interrupted, the line out relay will deenergize and will be placed in the normally open position.

At this point it should be noted that the normally open terminal of the set of contacts B of the audio silence relay 121 is connected by a line 135 to the line 124 which effectively shorts the closed and open terminals of the set of contacts B of the audio silence relay 121. Likewise, the normally open terminal of the set of contacts D of the reset relay 67 is connected by a line 136 to the line 126 which effectively shorts the open and closed terminals of the set of contacts D of the reset relay 67. This is done so that the coil 131 of the line out relay 130 will receive a signal regardless of the positions of the reset relay 67 and the audio silence relay 121. The reason for feeding the signal on the line 93 through the key switch 50, the audio silence 121, and the reset relay 67 and then into the line out relay 130, is to maintain a closed series loop through as many parts of the system as possible. This is explained in more detailbelow. Y My fig A line 137 is connected at one end to the normally open terminal of the set of contacts C of the line out relay 130 and at the other end to the line 66. A line 138 is connected at one end to the center terminal of the set of contacts C of the line out relay 130 and at the other end to a line out light indicator 139 located on the control panel 11. A line 142 is connected between the line 72 and the center terminal of the set of contacts A of the reset relay 67. A signal line 143 is connected between the normally open terminals of the sets of contacts A and B of the relay 75 associated with the station switches 21-30 and a line 144. One end of the line 144 is connected to the alarm terminal of the set of contacts E of the latching relay 101 and at the other end to one side of the inside alarm set switch 53. A line 145 is connected atone end to the center terminal of the set of contacts E of the latching relay 101 and at the other end to a line 146 one end of which is connected to the external signalling device 12. The external signalling device 12 may be a bell, a siren, a telephone connection to the police station, or any other suitable signalling means. Thus, taking the station switch 21 as an example, the normally open terminal of the set of contacts B of the relay 75 associated with the station switch 21 is connected to the normally open terminal on the set of contacts A of the relay 75 with the lines 147 and 148. The lines 147 and 148 are connected to the line 143. The other relays 75 associated with the other station switches 22-30 are connected to the line 143 in like manner.

The normally open terminal of each of the station switches 21-30 is connected to the normally closed terminals of the set of contacts B and C of their associated relays 75. Again, taking station switch 21 as an example, a line 150 is connected at one end to the normally open terminal of the station switch 21 and the other end to one end of each of the lines 151 and 152. The other ends of the lines 151 and 152 are connected to the normally closed terminals of the set of contacts C and B respectively of the associated relay 75. A line 155 is connected at one end to the center terminal of the set of contacts B of the relay 75 and at the other end to a light indicator 156 located on the control panel 11. Similarly, light indicators 157-165 associated with the other station switches 22-30 are also located on the control panel 11. A line 166 is connected at one end to the line 155 and at the other end to the coil 76 of the relay 75.

OPERATION IN THE BURGLAR ALARM MODE The operation of the surveillance and alarm system in the burglar mode will now be described. This mode is used as for example, where the building in which the alarm system is installed is to be left unoccupied for a period of time. With all of the windows and doors and other locations where the station switches are located secured and the on-off switch 51 on the control panel 11 closed, the person setting the alarm leaves the building through the door where the key switch is located. After closing the door behind him and using his key he locks the key switch 50in the burglar alarm position.

With the on off switch 51 closed and the key switch 50 in the alarm position, power is supplied to the system as described above. The operation of the system will now be explained where an entry is made through one of the stations where the station switches are located. Since the circuits of each of the station switches 21-30 and their associated relays 75 are identical, it is only necessary to explain the operation of one of the station switches and its associated relay 75 where an entry occurs where that station switch is located. Assume that station switch 21 is positioned at a window in the building and that an entry is made through that window. The station switch 21 is so positioned that if the window at which it is located is opened, the station switch 21 moves from its normally closed to its normally open position. The signal on the line 85 will now be fed through the center and normally open terminals of the station switch 21 through the lines 150 and 152, the normally closed and center terminals of the set of contacts B of the relay 75, the lines 155, 166 to the coil 76 of the relay 75. This will cause the coil 76 to energize placing the relay 75 in its normally open position. With the line 155 connected to the light indicator 156 on the control panel 11, whenever a signal is applied to the coil 76 of the relay 75 associated with the station switch 21, the light 156 associated with the station switch 21 will light, indicating the station through which entry was made. I

With the relay 75'associated with the station switch 21 in the normally open position the signal on the line 70 is fed through the line 80, the center and normally open terminals of the set of contacts A of the relay 75, the lines 148 and 147, the normally open and center terminals of the set of contacts B of the relay 75, and the lines 155 and 166 to the coil 76 of the relay 75, holding the relay 75 in the normally open position. The signal on the normally open terminal of the set of contacts A of the relay 75 is also fed through the line 148 and the signal line 143, the line 144 (and remembering that the latching relay 101 is in the alarm position) the alarm and center terminals of the set of contacts E of the latching relay 101 and the lines 145 and 146 to the external signalling device 12. Hence, whenever one of the station switches is placed in its normally open position, such as when entry is made at one of the stations, the external signalling device 12 is energized and an appropriate light on the control panel 11 indicates the station through which entry was made. Once any one of the relays 75 is activated by placing one of the station switches 21-30 in the normally open position, the relay will stay activated and the external signalling device 12 will remain on even though the station switch is returned to its normally closed position; that is, even though the door or window is closed. In other words, once the alann is triggered it stays on .until the holding signal is cut, such as with the reset switch 54 as will be described.

It is important to know, however, not only that an entry has been made, but how many and where the entries were made should there be more than one. For this reason it is important to keep the series loop circuit energized so that entry at any one or all of the other stations can be detected. This result is accomplished by connecting one end of the line 87 to the normally open terminal of the set of contacts D of the relay 75 associated with the station switch 21 as stated above. When entry is made at the station switch 21, and the station switch 21 is placed in its normally open position, the signal on the line 87 is fed through the normally open and center terminals of the set of contacts D of the relay 75 associated with the station switch 21 through the line 89 to the center terminal of the station switch 22. Hence, it can be seen that with the station switch 21 in either the nonnally open or the normally closed position, a signal is maintained on the line 89, and the series loop circuit remains energized. With the series loop circuit so energized, an entry at one or more of the other stations will be indicated by the appropriate lights on the control panel 11 in the same manner as was described with respect to station switch 21. This feature of the invention proves very useful in determining how many entries there were and the location of the intruder should he still be in the building. For example, when the alann goes off, the police can enter the building, look at the control panel and determine immediately where the entries occurred, and, if station switches are appropriately located at the internal doors of the building, the general location in the building of the intruder.

The purpose of the capacitor 71 is to maintain the voltage on the coil 131 of the line out relay during the period of time that it takes for any of the station switches 21-30 and their associates relays 75, the reset relay 67, the audio silence relay 121, the power supply relay 34, orthe key switch 50 to switch from one position to another. lf the capacitor 71 was not in the circuit, the coil 13] of the line out relay 130 could lose its signal and deenergize to the normally open position every time one of these switches or relays changed positions, causing the external signalling device 12 to become energized and the line out indicator 139 on the control panel 11 to light. Another purpose of the capacitor 71 which has already been described, is to supply an initial pulse to the coil 131 for placing the line out relay 130 in the normally closed position.

The purpose of the line out relay 130 is to indicate whenever the series loop circuit is opened. This could occur where the station switch, at the location where the entry was made, opens, but fails to make contact in the normally open position, where the intruder cuts one of the lines in the series loop circuit, breaks one of the lines or the wiper arm 60 while tampering with the key switch 50, or where the case interlock switch 127 is opened. The case interlock switch is mounted at the box where the relays used in the system are located, and is positioned so that it is closed when the cover is on the relay box and open when the cover is removed. Thus, if an intruder attempts to remove the relay box cover the case interlock switch 127 will open. Any of these occurrences will interrupt the circuit removing the signal at the center and normally closed terminals of the set of contacts A of the line out relay 130, the lines 132 and 73 and the coil 131. The line out relay 130 will thereby become deenergized placing it in the normally open position. When this occurs, two things happen: the signal on the line 66 is fed through the line 137, the normally open and center terminals of the set of contacts C of the line out relay 130, and the line 138 to the line out indicator 139 on the control panel 11, causing the line out indicator 139 to light. Also, the signal on the line 70 is fed through the center and normally open terminals of the set of contacts B of the line out relay 130, a line 167, the lines 143 and 144, the alarm and center terminals of the set of contacts E of the latching relay 101, and the lines 145 and 146 to the external signalling device 12. Therefore, whenever a break occurs in one of the lines of the series loop circuit the line out relay 130 will deenergize causing the external signalling device 12 to go on and the line out indicator 139 on the control panel 11 to light. The capacitor 71 prevents a false indication should only a temporary interruption occur in the series loop circuit as described above.

SURVEILLANCE MODE The surveillance mode is used where it is not necessarily desirable to set off an external alarm, but it is desirable to keep surveillance on the building. For example, a night watchman in a commercial office building can maintain surveillance by simply observing the control panel 11. The control panel 11 could be located in any convenient place such as the lobby of the building or the security office. This mode could also be used by a homeowner. The control panel 11 could be located in the bedroom.

The manual switches for the surveillance mode are positioned with the on off switch 51 closed, as in the burglar alarm mode, and the key switch 50 in the surveillance position. The remaining manual switches such as the panic switch 52, the inside alarm set switch 53, the reset switch 54, the audio release switch 55 and the test switch 56 are all set in the open position.

With the on-off switch 51 closed, the signal from the power supply 10 is fed through the line 40, the on-off switch 51, the line 66, the reset relay 67, the line 70, to each of the relays 75, and also through the line 85 and the series loop circuit to the line 93 as described in detail for the burglar alarm mode.

With the key switch 50 set to the surveillance position, that is, with the wiper arm 60 of the key switch 50 connecting the terminals 61 and 169, the signal on the line 93 is fed through the key switch 50 and a line 169 to the alarm terminal of the set of contacts B of the latching relay 101. Since the latching relay 101 was in the alarm position prior to placing the key switch 50 in the surveillance position, the signal on the line 168 is fed through the alarm and center terminals of the set of contacts B of the latching relay 101 and a line 170 to the surveillance coil 102 of the latching relay 101. Also, when the key switch 50 was placed from the alarm to the surveillance position, the signal was removed from the alarm coil 103 of the latching relay 101 thereby deenergizing the alarm coil 103. With a signal on the surveillance coil 102, the surveillance coil 102 becomes energized placing the latching relay 101 in the surveillance position. The signal on the line 169 is also fed through a line 172, a diode 173, and a line 174 to the line 120 and so on through the remainder of the series loop circuit maintaining a signal in the series loop circuit as was the case in the burglar alarm mode.

An internal signalling device, such as a buzzer 180 is also provided. The buzzer 180 is shown on the drawing mounted on the control panel 11 although it could be mounted in any convenient location in the building. The buzzer 180 is electrically connected by a line 181 to the normally closed terminal of the set of contacts A of the audio silence relay 121. The center terminal of the set of contacts A is connected by a line 182 to the signal line 143.

OPERATION IN THE SURVEILLANCE MODE Again, assume that an entry occurs at the location of the station switch 21. Just as in the burglar alarm mode, the station switch 21 will be placed in the nonnally open position which will cause the coil 76 of the amociated relay 75 to energize placing the relay 75 in the normally open position. In addition to energizing the coil 76 of the relay 75, it will cause the corresponding light 156 on the control panel 11 to light, thereby indicating where the entry occurred. Also, as described in the burglar alarm mode above, a signal will appear on the signal lines 143 and 144. However, unlike in the burglar alarm mode, in the surveillance mode the latching relay 101 is in the surveillance position which opens the alarm and center terminals of the set of contacts E of the latching relay 101. Hence, the signal on the line 144 cannot feed through the alarm and center terminals of the set of contacts E of the latching relay 101 and the lines 145 and 146 to the external signalling device 12. In other word, the external signalling device 12 will not operate in the surveillance mode. However, the signal on the line 143 will be fed through the line 182, the center and normally closed terminals of the set of contacts A of the audio silence relay 121, through the line 181 to the buzzer 180. The buzzer 180 acts as a sound signal to alert the watchman that an entry has been made and to look at the control panel 11. Just as in the burglar alarm mode the lights on the control panel 11 will indicate where and how many entries there were and locate the position of the intruder in the building. If the line out relay should become deenergized placing it in the normally open position, such as if one of the lines in the series loop circuit is cut, this will energize the signal line 143 as described in the burglar alarm mode, which will energize the buzzer 180. The line out indicator 139 will also light as described above.

Therefore, it can be seen that the surveillance mode is used primarily for the purpose of keeping surveillance over the building and not for the purpose of setting off an external alarm. However, two methods are provided for setting off the external signalling device 12 in conjunction with the surveillance mode if desired.

PANIC MODE One method is to simply manually close the panic switch 52. With the panic switch 52 closed, the signal on the line 40 is fed through the line 63, a line 185, the panic switch 52, a line 186, and a line 146 to the external signalling device 12. No matter what mode the system is in, closing the panic switch 52 will apply the signal from the power supply 10 directly to the external signalling device 12. Hence, closing the panic switch 52 will energize the external signalling device 12 even where the rest of the system remains undisturbed. The panic switch 52 could be used for example, where prowlers are observed outside the building, but no entry has been made.

INSIDE ALARM SET MODE Another way to set off the external signalling device 12 in the surveillance mode, is to close the inside alarm set switch 53. With the inside alarm set switch 53 closed, whenever a signal appears on the line 143 it will be fed through the line 144, the inside alarm set switch 53, a line 187, and the lines 145 and 146 to the external signalling device 12. However, unlike the panic switch 52, the inside alarm set switch 53 activates the external signalling device 12 only when a signal is present on the signal line 143, which is when one of the station switch relays 75 is energized or the line out relay 130 deenergized. Therefore, the external alarm circuit can be activated in the surveillance mode by simply closing the inside alarm set switch 53 or the panic switch 52.

AUDIO RELEASE MODE Once the internal buzzer 180 has been energized and has alerted the person in the building that an entry has been made and to watch the control panel 11, the buzzer 180 has served its purpose. It may, therefore, be desirable to deenergize the internal buzzer 180 after it has signalled an alert. This can be accomplished in any of the modes by simply closing the audio release switch 55. With the audio release switch 55 closed, the voltage on the signal line 143 is fed through a line 190, the audio release switch 55 and the lines 191 and 192 to the coil 122 of the audio silence relay 121. The coil 122 is thereby energized placing the audio silence relay 121 in the normally open position. When this occurs, the contact between the center and normally closed terminals of the set of contacts A of the audio silence relay 121 is broken and the signal to the line 181 and the internal buuer 180 is interrupted thereby deenergizing the buzzer 180. On end of the line 191 is connected to the normally open terminal of the set of contacts A of the audio silence relay 121, so that when the audio silence relay 121 is energized the signal on the line 182 will be fed through the lines 191 and 192 to the coil 122 to hold the relay 121 in the normally open position. Of course, the lights on the control panel 1 1 continue to indicate the number and location of entries made since the audio release switch 55 does nothing to remove the signals to the light indicators.

TEST Moon The test mode is provided for the purpose of insuring that each of the relays at the various station switches 21-30 are operating properly. The manual switches for the test mode are positioned with the on-off switch 51 and test switch 56 closed, the key switch 50 in the surveillance position and all of the other manual switches open. With the on-off switch 51 and the test switch 56 closed, the signal on the line 63 is fed through the line 64, the on-off switch 51, the line 65, a line 193, the test switch 56 and a line 194 to the center terminal of the set of contacts C of the corresponding relay 75 to the station switch 21. With the station switch 21 and its corresponding relay 75 in the normally closed position the signal on the test line 194 is fed through the center and normally closed terminals of the set of contacts C of the relay 75, the lines 151 and 152, the normally closed and center terminals of the set of contacts B of the relay 75, and lines 155 and 166 to the coil 76 of the relay 75. The coil 76 is thereby energized placing the relay 75 in the normally open position. The signal on the line 155 lights the corresponding light indicator 156 on the control panel 11 indicating that the coil 76 of the relay 75 is receiving a signal. With the relay 75 now in the normally open position and held in the nonnally open position with the signal on the line 80 as described above, the signal on the test line 194 is fed through the center and normally open terminals of the set of contacts C of the relay 75 associated with the station switch 21 and a line 195 to the center terminal of the set of contacts C of the relay 75 associated with the station switch 22. Just as with the relay 75 associated with the station switch 21, the relay 75 associated with the station switch 22 will now energize and the corresponding light 157 on the control panel 11 will light, indicating that the coil 76 of the relay 75 associated with the station switch 22 is receiving a signal and that the relay 75 associated with station switch 21 is operating correctly. The test signal will then be fed to the next station switch relay, and so on to the next, until all of the station switch relays have been energized as will be indicated by the successive lighting of the light indicators 156-165 on the control panel 11. Thus, when the test switch is closed, the location indicator lights 156-165 on the control panel 11 should indicate in sequence that each of the relays associated with the station switches 21 through 30 is operating properly. if for example, only the indicators 156-159 associated with the station switches 21-24 should light, this is a good indication that the relay 75 associated with the station switch 25 is stuck in the normally closed position.

The burglar alarm and surveillance modes can also be used as an easy and convenient method of testing and trouble shooting the system.

ill)

Suppose the burglar alarm mode is to be used. Under normal operation of the system, one of the station switches 2140 is located at the same door with the key switch 50, for example, station switch 22. With the on-off switch 51 closed, when the door is opened (the key switch 50 being in the surveillance position), the station switch 22 will be placed in its normally open position causing the internal buzzer 180 to sound just as described in the surveillance mode. The sound of the buzzer 180 is an indication that a large part of the system is operating correctly. When the door is closed placing the station switch 22 in its normally closed position and the key switch 50 placed in the alarm position, the coil 68 of the reset relay 67 is energized, placing the reset relay 67 in the normally open position as described in the burglar alarm mode. With the reset relay 67 in the normally open position there is no contact between the center and normally closed terminals of the set of contacts C of the reset relay 67, and the signal on the line 66 cannot get through the reset relay 67 to the lines 69 and 70 and the holding line 81. Hence, the signals on the lines 69, 70, and 81 are interrupted, and the relay 75 associated with the station switch 22 will be reset to its normally closed position. This will cause the buzzer 180 to lose its signal.

Therefore, it can be seen that the reason for feeding the power signal through the reset relay 67 is to provide an automatic signal release and resetting of the station switch relays 75 to their normally closed positions when the key switch 50 is placed in the burglar alarm position.

With respect to the surveillance mode, suppose for example, that all of the windows and doors where the station switches 2130 are located are closed, but that the external signalling device 12 goes off when the key switch 50 is placed in the burglar alarm position or the internal buzzer 180 sounds when the system is in the surveillance mode. This could mean that one of the stationswitches 21-30 is stuck in the normally open position. This can be easily determined by placing the system in the surveillance mode and observing the location indicators 156-165 on the control panel 11. If for example, the indicator 160 associated with the station switch 25 is on, this indicates that the station switch 25 is stuck in the normally open position.

As another example, suppose one of the station switches is intermittent, that is, suppose it goes to its normally open posi tion for a few seconds and then returns to its normally closed position. lnten'nittent problems such as this can be the most difiicult to solve. However, by using the surveillance mode, such intermittence will be permanently recorded by the appropriate light indicator on=the control panel 11, for when the switch is in its normally open position, the appropriate indicator will light and remain lit as an indication of which of the switches is malfunctioning.

Still another example of how the surveillance mode can be used to trouble shoot the system is where a break occurs in the closed series loop circuit as indicated by the line out indicator 139. The locations of the break can be ascertained at least within limits by placing the system in the surveillance mode and opening the windows and doors where the station switches are located. As described above, power is supplied to the closed series loop circuit even when one or more of the station switches are placed in the normally open position. Thus, if for example, a break occurs in the loop circuit between station switches 29 and 30, the light indicators 156-164 will light, but not light indicator 165. This indicates that the break is somewhere between station switches 29 and 30.

Hence, the proper use of the burglar alarm, surveillance and test modes can greatly reduce maintenance and repair time by testing the system and pinpointing the trouble.

THE RESET RELEASE The reset switch 54 is located on the control panel 11, and is provided for the purpose of resetting the relays 75 associated with each of the station switches 21-30. Again, using station switch 21 as an example, suppose that the station switch 21 is located at a window and an entry is made through the window causing the station switch 21 to be placed in its normally open position and energizing the relay 75. Once the relay 75 is energized, the signal on the line 80 will hold the relay 75 in its normally open position. Therefore, even if the window at which the station switch 21 is located is closed, the relay 75 will remain in the normally open position. The only way the relay 75 can be placed back in its normally closed position is by removing the holding signal on the line 80. This can be accomplished by closing the reset switch 54 on the control panel 11. The reset switch 54 must be operated with the on-off switch closed. With both the reset switch 54 and the on-off switch 51 closed, the signal on the line 63 is fed through the line 64, the on-off switch 51, the line 65, a line 200, the reset switch 54, and a line 201 to the center terminal of the set of contacts A of the latching relay 101. With the latching relay 101 in the surveillance position, which would be the case since the key switch 50 would be in the surveillance position, the signal on the line 201 is fed through the center and surveillance terminals of the set of contacts A of the latching relay 101 and through the line 107 to the coil 68 of the reset relay 67. The coil 68 is thereby energized placing the reset relay 67 in the normally open position, interrupting the signal on the line 66 at the center terminal of the set of contacts C of the reset relay 67. This will cause the lines 69 and 70 and the holding line 80 to lose their signal and the relay 75 associated with the station switch 21 to reset to its normally closed position. The other relays 75 associated with the station switches 22-30 reset in the same manner.

It should be obvious, however, that the reset switch 54 will reset the station switch relays 75 only if the condition causing one or more of the relays to be placed in its normally open position is corrected. Hence, if one of the doors or windows where the station switches 21-30 are located is left open, closing the reset switch 54 will not reset the relays for when the signal release switch is released or opened, those relays which were previously placed in the normally open position will return to that position.

It is also to be noted that the reset switch 54 will not operate to reset the relays 75 where the key switch 50 is in the burglar alarm position. This is so because with the key switch 50 in the burglar alarm position the latching relay 101 is in the alarm position and the signal on the line 201 can not get through the relay 101 to the coil 68 of the reset relay 67. Thus, an intruder cannot deactivate the external signalling device 12 by closing the reset switch 54.

Various changes and modifications may be made within this invention as will be readily apparent to those skilled in the art. Such changes and modifications are within the scope and teaching of this invention as defined by the claims appended hereto.

What is claimed is:

1. A surveillance and alarm system for a building comprising a plurality of entry responsive means, a line out responsive means, the entry responsive means and line out responsive means being electrically connected together in a normally closed series loop circuit, the line out responsive means being responsive to an interruption in the signal in the closed series loop circuit, means associated with each of the entry responsive means for supplying power to the remaining entry responsive means in the closed series loop circuit when one or more of the entry responsive means are actuated, external signalling means responsive to the actuation of any of the entry responsive means or the line out responsive means, means responsive to the actuation of each of the entry responsive means for indicating the number and location of the entries, and means for supplying power to the system.

2. A surveillance and alarm system of claim 1 including means for holding activated external signalling means and indicating means in the activated condition.

2. The surveillance and alarm system of claim 2 including means for releasing the holding means.

4. The surveillance and alarm system of claim 2 including means for setting the system in any one of several mode variations.

5. The surveillance and alarm system of claim 4 wherein one mode variation is with both the external signalling means and the indicating means responsive, and another mode variation is with just the indicating means responsive.

6. The surveillance and alarm system of claim 4 wherein the means for setting the system in any one of several mode variations includes a key switch having a surveillance and an alarm position.

7. The surveillance and alarm system of claim 6 including means for releasing the holding means, wherein said releasing means is responsive to placing the key switch in the alarm position providing automatic resetting of the entry responsive means when the key switch is placed in the alarm position.

8. The surveillance and alarm system of claim 6 wherein the means for setting the system in any one of several mode variations further includes means responsive to the key switch setting for selecting the responsiveness of the external signalling means.

9. The surveillance and alarm system of claim 8 including a means for making the external signalling means responsive to the actuation of the entry responsive means or line out responsive means regardless of the mode setting of the key switch.

10. The surveillance and alarm system of claim 9 wherein the last named making means includes an inside alarm set switch which when closed makes the external signalling means responsive to the actuation of the entry responsive or line out responsive means regardless of the mode setting of the key switch.

11. The surveillance and alarm system of claim 9 including indicating means responsive to the actuation of the line out responsive means, and internal sounding device responsive to the actuation of the entry responsive means or the line out responsive means, means for deactivating the internal sounding device, and means for holding activated external signalling means and indicating means in the activated condition.

12. The surveillance and alarm system of claim 2 including a panic switch which when closed connects a signal from the power supply means directly to the external signalling means.

13. The surveillance and alann system of claim 2 including indicating means responsive to the actuation of the line out responsive means.

14. The surveillance and alarm system of claim 13 including a case interlock switch in the series loop circuit, whereby opening the case interlock switch interrupts the power signal in the closed series loop circuit causing the line out responsive means to actuate and the external signalling means and the line out indicating means to respond.

15. The surveillance and alarm system of claim 2 including an internal sounding device responsive to the actuation of the entry responsive means or the line out responsive means.

16. The surveillance and alarm system of claim 15 including means for deenergizing the internal sounding device.

17. The surveillance and alarm system of claim 2 including means for testing the operation of the entry responsive means.

18. The surveillance and alarm system of claim 1 wherein the power supply includes an auxiliary battery power supply, a rectified line power supply, and means for automatically switching from the rectified line power supply to the auxiliary battery power supply when the line power be interrupted.

19. The surveillance and alarm system of claim 2 including means for preventing the line out responsive means from responding to short temporary interruptions in the signal in the closed series loop circuit, and for providing an exciting signal to the line out responsive means placing the line out responsive means in its set position immediately upon energizing the system.

20. The surveillance and alarm system of claim 2 wherein the plurality of entry responsive means comprises a plurality of station switches having normally closed and normally open positions, and a relay associated with each station switch having normally closed and normally open positions and a plurality of sets of contacts, each station switch and relay combination being electrically connected through normally closed terminals in a closed series loop circuit; and the line out responsive means comprises a line out relay having normally closed and normally open positions and a plurality of sets of contacts, the coil of the line out relay being electrically connected in the closed series loop circuit, whereby the line out relay is energized and in the normally closed position.

21. The surveillance and alarm system of claim 20 wherein the means associated with each of the entry responsive means comprises means associated with each station switch and relay combination for supplying a power signal to the series loop circuit when any of the station switch and relay combinations are placed in the normally open position.

22. The surveillance and alarm system of claim 21 wherein the external signalling means is responsive to the placing of any station switch and relay combination in the normally open position, or the placing of the line out relay in the normally open position, and the indicating means for indicating the number and location of the entries is responsive to the placing of any of the station switch and relay combinations in the normally open position.

23. The surveillance and alarm system of claim 2 wherein the indicating means comprises a light indicator for each station switch in the system, means electrically connecting each light indicator to its associated station switch and relay combination, and means for energizing each light indicator whenever its associated station switch and relay combination is placed in the normally open position.

24. The surveillance and alarm system of claim 23 including a line out indicator, the line out indicator being electrically connected to the line out relay, and means for energizing the line out indicator whenever the line out relay is placed in its normally open position.

25. The surveillance and alarm system of claim 24 wherein the light indicator associated with each station switch and the line out indicator are mounted on a control panel.

26. The surveillance and alarm system of claim 23 including a key switch having an alarm and a surveillance position, an on-off switch having an open and closed position, means responsive to the placing of the on-ofi" switch in its closed position for providing a signal to the key switch, a latching relay having an alarm and a surveillance position, the position of the latching relay being determined by the position of the key switch, and means responsive to the placing of the latching relay in its alarm position for supplying a signal to the closed series loop circuit, whereby closing the on-off switch provides a signal to the key switch which when placed in its alarm position will cause the latching relay to be placed in its alarm position applying a signal to the closed series loop circuit.

27. The surveillance and alarm system of claim 26 including means responsive to the placing of the on-off switch in its closed position for providing a signal directly to the closed series loop circuit.

28. The surveillance and alarm system of claim 27 wherein a signal line is electrically connected to each station switch and relay combination and the line out relay and becomes energized when any of the station switch and relay combinations or line out relay are placed in the normally open condition, and including means for connecting the signal line to the external signalling means through the latching relay, the last-mentioned connecting means providing activation of the external signalling means with the key switch in the alarm position but not in the surveillance position.

29. The surveillance and alarm system of claim 28 including an inside alarm set switch having an open and a closed position, the inside alarm set switch connected between the signal line and the external signalling means and across the latching relay, whereby closing the inside alarm set switch, allows any signal on the signal line to bypass the latching relay and energize the external signalling means regardless of the position setting of the key switch.

30. The surveillance and alarm system of claim 28 including an internal sounding device connected to the signal line and activated whenever there is a signal on the signal line.

31. The surveillance and alarm system of claim 30 including an audio silence relay having a normally closed and a normally open position and at least one set of contacts, the internal sounding device being connected to the signal line through normally closed contacts of the audio silence relay.

32. The surveillance and alarm system of claim 31 including an audio release switch having a closed and an open position, means connecting the power supply signal to the coil of the audio silence relay when the audio release switch is closed, whereby closing the audio release switch places the audio silence relay in the normally open position, interrupting the signal from the signal line to the internal sounding device, deenergizing the sounding device.

33. The surveillance and alarm system of claim 32 wherein the audio silence relay is provided with at least two sets of contacts and the series loop circuit is fed through the second set of contacts in the audio silence relay and the key switch.

34. The surveillance and alarm system of claim 23 including means for holding each of the relays associated with the station switches in the normally open position once it has been placed in that position.

35. The surveillance and alarm system of claim 34 including means for releasing the holding means, allowing the relays to return to their normally closed position.

36. The surveillance and alarm system of claim 35 wherein the holding means includes a holding line, a reset relay having a normally closed and normally open position and a plurality of sets of contacts, and means for applying a holding signal to the holding line through normally closed contacts of the reset relay.

37. The surveillance and alarm system of claim 36 wherein the means for releasing the holding means includes a reset switch having an open and a closed position and means connecting the power supply signal to the coil of the reset relay when the reset switch is closed, placing the reset relay in it normally open position, whereby closing the reset switch and placing the reset relay in the normally open position interrupts the holding signal and resets the relays associates with the plurality of station switches.

36. The surveillance and alarm system of claim 37 wherein the series loop circuit is fed through a set of contacts in the reset relay.

39. The surveillance and alarm system of claim 36 including means for applying a signal to the coil of the reset relay through the key switch when placed in the alarm position, whereby placing the key switch in the alarm position places the reset relay in the normally open position interrupting the holding signal thereby providing automatic resetting of the relays associated with the station switches.

40. The surveillance and alarm system of claim 23 including a panic switch which when closed connects the signal from the power supply directly to the external signalling means.

41. The surveillance and alarm system of claim 23 wherein the power supply includes an auxiliary battery power supply, a rectified line power supply, and means for automatically switching from the rectified line power supply to the auxiliary battery power supply when the line power be interrupted.

42. The surveillance and alarm system of claim 23 including a test switch having a closed and an open position, and means for connecting the power signal to the coils of the relays associated with the station switches when the test switch is closed.

43. The surveillance and alarm system of claim 20 wherein the system relays are mounted in a box and including a case interlock switch having a closed and an open position connected in the series loop circuit and means for mounting the case interlock switch in the box so that the case interlock switch is placed in the open position interrupting the signal in the closed series loop circuit causing the line out relay to be placed in its normally open position when the cover of the box is removed. 

1. A surveillance and alarm system for a building comprising a plurality of entry responsive means, a line out responsive means, the entry responsive means and line out responsive means being electrically connected together in a normally closed series loop circuit, the line out responsive means being responsive to an interruption in the signal in the closed series loop circuit, means associated with each of the entry responsive means for supplying power to the remaining entry responsive means in the closed series loop circuit when one or more of the entry responsive means are actuated, external signalling means responsive to the actuation of any of the entry responsive means or the line out responsive means, means responsive to the actuation of each of the entry responsive means for indicating the number and location of the entries, and means for supplYing power to the system.
 2. A surveillance and alarm system of claim 1 including means for holding activated external signalling means and indicating means in the activated condition.
 2. The surveillance and alarm system of claim 2 including means for releasing the holding means.
 4. The surveillance and alarm system of claim 2 including means for setting the system in any one of several mode variations.
 5. The surveillance and alarm system of claim 4 wherein one mode variation is with both the external signalling means and the indicating means responsive, and another mode variation is with just the indicating means responsive.
 6. The surveillance and alarm system of claim 4 wherein the means for setting the system in any one of several mode variations includes a key switch having a surveillance and an alarm position.
 7. The surveillance and alarm system of claim 6 including means for releasing the holding means, wherein said releasing means is responsive to placing the key switch in the alarm position providing automatic resetting of the entry responsive means when the key switch is placed in the alarm position.
 8. The surveillance and alarm system of claim 6 wherein the means for setting the system in any one of several mode variations further includes means responsive to the key switch setting for selecting the responsiveness of the external signalling means.
 9. The surveillance and alarm system of claim 8 including a means for making the external signalling means responsive to the actuation of the entry responsive means or line out responsive means regardless of the mode setting of the key switch.
 10. The surveillance and alarm system of claim 9 wherein the last named making means includes an inside alarm set switch which when closed makes the external signalling means responsive to the actuation of the entry responsive or line out responsive means regardless of the mode setting of the key switch.
 11. The surveillance and alarm system of claim 9 including indicating means responsive to the actuation of the line out responsive means, and internal sounding device responsive to the actuation of the entry responsive means or the line out responsive means, means for deactivating the internal sounding device, and means for holding activated external signalling means and indicating means in the activated condition.
 12. The surveillance and alarm system of claim 2 including a panic switch which when closed connects a signal from the power supply means directly to the external signalling means.
 13. The surveillance and alarm system of claim 2 including indicating means responsive to the actuation of the line out responsive means.
 14. The surveillance and alarm system of claim 13 including a case interlock switch in the series loop circuit, whereby opening the case interlock switch interrupts the power signal in the closed series loop circuit causing the line out responsive means to actuate and the external signalling means and the line out indicating means to respond.
 15. The surveillance and alarm system of claim 2 including an internal sounding device responsive to the actuation of the entry responsive means or the line out responsive means.
 16. The surveillance and alarm system of claim 15 including means for deenergizing the internal sounding device.
 17. The surveillance and alarm system of claim 2 including means for testing the operation of the entry responsive means.
 18. The surveillance and alarm system of claim 1 wherein the power supply includes an auxiliary battery power supply, a rectified line power supply, and means for automatically switching from the rectified line power supply to the auxiliary battery power supply when the line power be interrupted.
 19. The surveillance and alarm system of claim 2 including means for preventing the line out responsive means from responding to short temporary interruptions in the signal in the closed series loop circuit, and for providing an exciting signal to the line out respOnsive means placing the line out responsive means in its set position immediately upon energizing the system.
 20. The surveillance and alarm system of claim 2 wherein the plurality of entry responsive means comprises a plurality of station switches having normally closed and normally open positions, and a relay associated with each station switch having normally closed and normally open positions and a plurality of sets of contacts, each station switch and relay combination being electrically connected through normally closed terminals in a closed series loop circuit; and the line out responsive means comprises a line out relay having normally closed and normally open positions and a plurality of sets of contacts, the coil of the line out relay being electrically connected in the closed series loop circuit, whereby the line out relay is energized and in the normally closed position.
 21. The surveillance and alarm system of claim 20 wherein the means associated with each of the entry responsive means comprises means associated with each station switch and relay combination for supplying a power signal to the series loop circuit when any of the station switch and relay combinations are placed in the normally open position.
 22. The surveillance and alarm system of claim 21 wherein the external signalling means is responsive to the placing of any station switch and relay combination in the normally open position, or the placing of the line out relay in the normally open position, and the indicating means for indicating the number and location of the entries is responsive to the placing of any of the station switch and relay combinations in the normally open position.
 23. The surveillance and alarm system of claim 2 wherein the indicating means comprises a light indicator for each station switch in the system, means electrically connecting each light indicator to its associated station switch and relay combination, and means for energizing each light indicator whenever its associated station switch and relay combination is placed in the normally open position.
 24. The surveillance and alarm system of claim 23 including a line out indicator, the line out indicator being electrically connected to the line out relay, and means for energizing the line out indicator whenever the line out relay is placed in its normally open position.
 25. The surveillance and alarm system of claim 24 wherein the light indicator associated with each station switch and the line out indicator are mounted on a control panel.
 26. The surveillance and alarm system of claim 23 including a key switch having an alarm and a surveillance position, an on-off switch having an open and closed position, means responsive to the placing of the on-off switch in its closed position for providing a signal to the key switch, a latching relay having an alarm and a surveillance position, the position of the latching relay being determined by the position of the key switch, and means responsive to the placing of the latching relay in its alarm position for supplying a signal to the closed series loop circuit, whereby closing the on-off switch provides a signal to the key switch which when placed in its alarm position will cause the latching relay to be placed in its alarm position applying a signal to the closed series loop circuit.
 27. The surveillance and alarm system of claim 26 including means responsive to the placing of the on-off switch in its closed position for providing a signal directly to the closed series loop circuit.
 28. The surveillance and alarm system of claim 27 wherein a signal line is electrically connected to each station switch and relay combination and the line out relay and becomes energized when any of the station switch and relay combinations or line out relay are placed in the normally open condition, and including means for connecting the signal line to the external signalling means through the latching relay, the last-mentioned connecting means providing activation of the extErnal signalling means with the key switch in the alarm position but not in the surveillance position.
 29. The surveillance and alarm system of claim 28 including an inside alarm set switch having an open and a closed position, the inside alarm set switch connected between the signal line and the external signalling means and across the latching relay, whereby closing the inside alarm set switch, allows any signal on the signal line to bypass the latching relay and energize the external signalling means regardless of the position setting of the key switch.
 30. The surveillance and alarm system of claim 28 including an internal sounding device connected to the signal line and activated whenever there is a signal on the signal line.
 31. The surveillance and alarm system of claim 30 including an audio silence relay having a normally closed and a normally open position and at least one set of contacts, the internal sounding device being connected to the signal line through normally closed contacts of the audio silence relay.
 32. The surveillance and alarm system of claim 31 including an audio release switch having a closed and an open position, means connecting the power supply signal to the coil of the audio silence relay when the audio release switch is closed, whereby closing the audio release switch places the audio silence relay in the normally open position, interrupting the signal from the signal line to the internal sounding device, deenergizing the sounding device.
 33. The surveillance and alarm system of claim 32 wherein the audio silence relay is provided with at least two sets of contacts and the series loop circuit is fed through the second set of contacts in the audio silence relay and the key switch.
 34. The surveillance and alarm system of claim 23 including means for holding each of the relays associated with the station switches in the normally open position once it has been placed in that position.
 35. The surveillance and alarm system of claim 34 including means for releasing the holding means, allowing the relays to return to their normally closed position.
 36. The surveillance and alarm system of claim 35 wherein the holding means includes a holding line, a reset relay having a normally closed and normally open position and a plurality of sets of contacts, and means for applying a holding signal to the holding line through normally closed contacts of the reset relay.
 36. The surveillance and alarm system of claim 37 wherein the series loop circuit is fed through a set of contacts in the reset relay.
 37. The surveillance and alarm system of claim 36 wherein the means for releasing the holding means includes a reset switch having an open and a closed position and means connecting the power supply signal to the coil of the reset relay when the reset switch is closed, placing the reset relay in it normally open position, whereby closing the reset switch and placing the reset relay in the normally open position interrupts the holding signal and resets the relays associates with the plurality of station switches.
 39. The surveillance and alarm system of claim 36 including means for applying a signal to the coil of the reset relay through the key switch when placed in the alarm position, whereby placing the key switch in the alarm position places the reset relay in the normally open position interrupting the holding signal thereby providing automatic resetting of the relays associated with the station switches.
 40. The surveillance and alarm system of claim 23 including a panic switch which when closed connects the signal from the power supply directly to the external signalling means.
 41. The surveillance and alarm system of claim 23 wherein the power supply includes an auxiliary battery power supply, a rectified line power supply, and means for automatically switching from the rectified line power supply to the auxiliary battery power supply when the line power be interrupted.
 42. The surveillance and alarm system of claIm 23 including a test switch having a closed and an open position, and means for connecting the power signal to the coils of the relays associated with the station switches when the test switch is closed.
 43. The surveillance and alarm system of claim 20 wherein the system relays are mounted in a box and including a case interlock switch having a closed and an open position connected in the series loop circuit and means for mounting the case interlock switch in the box so that the case interlock switch is placed in the open position interrupting the signal in the closed series loop circuit causing the line out relay to be placed in its normally open position when the cover of the box is removed. 